Oxyfluoride glasses



Patented Dec. 11,1951

U NJT;;ED S TAT ES QE F ICE-j OXYFLUORIDE GLASSES Kuan-Han Sun, Pittsburgh, Pa and Maurice L Huggins, Rochester, N. Y, assignors to-iEastman Kodak-Company, RochesterQ-N; Yr, a. cor-o m ie iqno N w er e Application Deeember113, 1949, Serial No. 132,693 1 6 Claims. (01. HE 41 2,511,224, granted June: 13, 1950, which relates generically to glasses either consisting entire-r 1y; of fluorides, I or, containing predominantly fluoridewith smallamounts fof otherQeleiitrIo-l.

negative elements such as oxygen, and specifically toc difierent pure. fluoride glasses, The present.v

applicationis, specific to oxyrfluorideglasses.

This application is I to be distinguished. .frompatents, Sun 2,i30,539, granted November 11,

1947,; and; Sun .and Huggins 2,481,700, granted;

September 13, 1949, both relating to fiuophosphate glasses, and from-patents, Sun 2,456,033,

granted DecemberliQlQiS, and Sun 2,466,505,

granted April 5, 1949, both relating to fluoborate glasses, and from Sun 2,425,403, granted August 12, 1947, relating to fiuogermanate glasses, and rdmi l nflr filflflli r n ed Se em er 13, .4.9 relating ,to fiuosilicate glasses.

These patents he; applications, ,for which. were filed, aft r. he

patent application 568,314,- relate principally tqf lasses whichf are primarily, oxide. glasses, the.

ionic percentage offluorine being" inmost-cases,

much less than in. the. present case. Several. lot

these also have a much higher percentage of ialkali-metal fiuoridethan the. present glasses;

which have little or. no alkali metal.

In general, fluorides have very low optical dispersions and high Abbe values. While glasses made solely of fluorides have the greatest Abbe values, it hasbeen found, that a certain proportion of compounds known and frequently used in glass compositions are compatible with the fluorides and, if l introduced in minor amounts,

tend to, increase the stability of the glassandits;

resistance, to. Weathering. They do,l however.

reduce theAbbe value, but this is- Still-in an area,, different from, and above those ofnpreviously a known oxide glasses. The same generalization;

isltrue of the effector theaddition of ioxidesi'upon thepartial dispersion ratios in that these are closerlthan those of the pure fluoride glas sesto f those of previously known commercial glasses. By the addition of oxides in limited amounts to thefluorideglasses.given in any'of the examples in said prior application, it is possible to obtain glasses having properties intermedate tothose of pure fluoride glasses and known commercial glasseslfi The glass maker is "thus enabled to produce glasses having a wide variety'of properties suitable for combination with othergla'sses'in the design of objectives and other optical systemsr,

-ered by tho e g1as es e0nsistineeutirelv of fluom to illustrate and; explain; the ..novel; and desirable properties of ourv newtoxyefiuorideglasses. Fig.,=, 1 is. a chart,. the-@coordina-tes o-ofewhichiare n the refractive .index and; 1), theA-bbe value, ,ShOWz-s. L.

, ing the areas oft-these values, bothiioriprevious-m lycknown. and our-presentglassesl Fig. 2:-.is';.;a:; chart; theocoordinates; of wwhich arerv n, theppar-l tial dispersion ratioion .g, and F, iandav, .,the :Abbe value, illustrating the. relationubetween these. values.

There, are certainarelationships betweenithe-rl optical constants ofv a glass that-areespecially im; portant to optical desi nera. The, first ,0f: theS e. a is the relationship; between,them, and values,;

n isith ,reiraet vemdextieethesodium; Delio e and v isdefined as,

where m and no are the refractive indicesionm the F'- andC-lines,respectively.v

In Fig. 1,, a is: plottedeagainstwr Optioal designers would; likeuto have glasseslwithlpropern-iv ties representedby-points. scattered all over .the chart so that they might/choose;itwo orumorep glasses, 1 for, .use together, having any; desired combination-of, optical properties, In; practicehowever, the ,availabilityrofz glasses, withlrespectto theirn and 11 values, isntathenlimited;

In, Fig 1;. the, area. .A,' .,Ordinary1.-CQmmereiaL Glassesii. includes, WeibelieveLa-ll; glassesdisedl r optical designs ,up ,to about-111939.; The introduc.-.-:.= tion-tof, borate, glasses; particularly those.- alsoicona-l min rfi ffineljements,described, by; G.-;-W; :Morevas -in U; S. Reissue; gPatenllaNo. 21,175,; greatlyHex-a,

tendedthe area;,of:; available glasses, as. shown-e approximately; the area 11 in thercharti desig. nated Borate Glasses. Area Q-fPure;Fluorid&; Glasses? n ludes;i hesa prqxima eere ion covrides which. are 1 described application, No 56.53%? rea- J nelsldesi ei maifqx te r m f r he 1 l9P1 9Ph 9- 1 5 5 ve by e tfl 2A MQ0= lrElndi tesat approximate region for the fiuoborate glasses covered' by, Patent 2,556,033,, and area F includes the regions, of ,the .1"l uqph0$1 911, 11? o a 39 9, ngelst ug ilieaiaane oser mate .i lasses. These areas, v overlap and T are; not separately designated; 4 H h ie -.-s eated a wh nu n cate the values, for thesimf rly -designated ex amples given hereafteh. lt fi's ,to be ,-n0tedthat:, these include, a regionuG extending frorn ,th regionCpf the purefi uoride glassesfl'into th A, of ordinar ,commencial gl3Ss= and-also Vere, ,1 lap region. B, thus .afiordina as, poted, above, at i an e val s which ma be i m dbe. varying the components, and par ularly "the;-

These perples 4 y purely ionic in TABLE I It is to be understood that the various areas are approxi- They are intended merely to show graphically the general fields of interest and to show that the present glasses have a range of useful properties not found in m n 5 0 5 0 5 0 5 1 1 2 2 3 8 l e-1. e S dV- dS ye V.h y a; m mwmwwmm flmmmmmm mmmmmmm mmnmmmmmvcwam m mm m a .1 f O O l. t edd m .m wrshdw snwemmm .ty w e m ,m rs m m m m m ama am m m nm aw a m m mam w a u s n n ev. 3t d efl sfi fl e e e t .m u n a v .1 .1 a q c e d n W H S e S n r h e 0 6 r r u r Fe r 011 r 5 1 De e 0 6 u n S O a 81 0 m 61 S 0 8d d 8 O D e e m X m e a n r S1 0 a m 0 SS S n D .C at C n p e F a h s rreed 5t k fi u m so a o O 8 S ytn h h 60. C D v 2. S nhm 1 0d .1 C 1e e te r 1 .l. n n G v y an W .n ms F n oa nnd d e rea ul t 2n 0 ea F.m a dm co f y.1b. ea nt n ter femlafmDwhynamt ifiei and n m mm am mh mi 0 a W 0h ..u 0. .B e r a S a SdStb 2 i u e H r r a r O t at d .1 t n t d e a V 27% n e a S a n EM m m eh e S US n n e n t r 80 e n v E m n HEW 1 8 g .1 t S O a S u f n S em 6 n fl rfe3 or i h .1 e s s .mt n d ch mc ee.m t e V4 06 g, t ap sn l r 0 dr m l mun V I r icuolrlnnrlmqzdnf Y p a a C S.n.I HO p a u 1 n B n n t g l O 0 a 1 l p 8 e a gu fr Z1 I S 0 .1 s an. ad 0 Fvv w m w fi o r wn afir i o e phm uOO ir fi cae b r pu a s n dtsd w r lt F e 7SF n ST d mhfi pm m e .1 a .W u S n n u f v le f mi m S .1 d Ca 6 S g e a S 61 elf t 0 a 90 u d a t1 l 00 n s mmfime mmwn m wmmma m fi m m mmmmw m .m 0 uh 5h0n0 .m e r S uerh .mS aOO r nla. fif.l. .b nub nfi mG O gntnuv n O Oi e fgr C SbO, E Y t e la ..b 1 .l Wp g fip 1 en SO u ha a .1 wmm mmmsw nwmmmwmmwwmwwmumm msm mmwm mm mmmwmmmwm nrge t r6 I n. v Xa eu aL g nee .ln nb a a k h u en. e. vqhmb h aoxosatpw dy s a ulv .m mm srlaenatwng tg s T1.5% h ao=Jm e e m 01 y HIM rn a hu na q u by ro. u1 m u n I e 0 g e e m t 1 e t r V h S V n 6 Mi h 0 n d f 0 D n a m a m i 0 0 m 0 1 h C m n 0 1 h r t e t a n u ,tf. n n1 a e 0 b n e n ,n u p r S1 t l. m v/k cew. 8 0 HS ea mn le na maele me .1 0538 x uf oan m em ne m a m e hr t cb velmanebseutc m hufiwm umchnttiwemsditti u hs yAfi ree ah Regfiro e tlrteetsTin t r r n bTvihlegA F h r r e rn a. a e e e O S a ehe e I u a tohfi w WW Twnm mbew wwm fiflemvpb mcablw nhor hW OStS proportion of oxygen to fluorine.

mate and overlap more or less.

The above example are repeated below, the me examples being designated by the s In using ionic formulas and the ex-- pression ionic percentage, however, we do not wish to imply that the binding forces between adjacent atoms are necessaril character. The following Table V gives these ionic percentages for Examples 1, 2, 3, 5, 6, and 7, 75 Table VI gives the percentages for Exam numbered examples are given, assembled for con- 65 sa components of the batch. In each example the numbers with the proportions given as percent weight percentages are given in a column under ages f ions or atoms f each element. the letter and the corresponding mole may be called the ionic, atomic, or elemental centages under the letter M. In the first three centages. tables the 'n value is also given. The examples 70 of Tables I, II, and III are given in our application 568,314 and those of Table IV, which are not specifically claimed, are added as illustrative of compositions which we consider as within the scope of our claims.

. 8 and 8, and Table VII gives th 00133050460 for Examples 9, 10.9110 11. I

TABLE v" Iomc percentages TABLE VI Iomc percentages TABLE VII IOTLZC percentages In general, although'a glass maybe formed from a batch containing various components, these individual components do not exist as such in the final product. Itis more nearly correct to consider a glass as an irregular aggregate of:positive andnegative ions oratomsiBejt, Altf P+++++, F", 0, etc), althoughthe forces between adjacent atoms, especially betweemadjacent silicon, phosphorus, or sulfur atoms andoxygen atoms, are by no means purely ionicin character. For this reason, the ionic percentages or .atomic percentages used infI'ables, V VI, and VII are moresignificant than the weight and mole percentages used in Tables I, II, III, and IV.

In expressing the compositions in terms ofisiinple fluorides and oxides, we do not implyth'at these simple compounds are aecessaruy originally used in the actual batches. Complex fluorides, oxides, fluoroxides, mixed oxides, etc., (including those such as ammonium berylliumfiuoride'which decompose on'heating to give, besides the desired components, other compounds whichare removed by volatilization) may be used injsuch*proportions as to give the desired final compositions. Wholly volatile iiuoridessuch ammonium fl'uo: ride, ammonium hydrogen'fiuoride, etc.,niaybe added for other advantageous efi'ects without 109 te ll-yaiifecting the final composition, reover', in a glass consisting of a number or components the same final composition can be arrived at in various ways by using different combir'iations of the same or different compound in the batch. We do not wish to restrict our claims to any particular combination of compounds used in the batch. For instance, Examples 1, 2, and 3 were made using aluminum metapho'sphate in addition to variou metallic fluorides. Identical glasses might have been made, however, using appropriate amounts of phosphates of other elements (beryllium, magnesium, calcium, stron} tium, barium, lead, lanthanum, cerium, and thorium) introducing aluminum as aluminum fluoride; One might also produce these glasses, introducing no phosphate, as such, in the batch, but instead the oxides of phosphorus and of "a metal, as in Examples 0 to '7, inclusive, or any of the metals Whose fluorides are mentioned, or appropriate amounts of fluoride or oxyfluor'ide of pentavalent phosphorus with oxides of some of the other elements which will be in the glass product.

Furthermore, instead of introducing oxides such as LazOa together with fluorides of the other metals mentioned, as in Example 9, the lanthanum may be introduced entirely as a fluoride with the oxides of one or more of the other metals. The ultimate composition of the resulting glass would be the same. The composition is not, therefore, limited to the use of any specific oxide or oxides. In such cases as these the advantage of expressing compositions in terms or" relative amounts of ions or atoms is obvious. The general principle is also applied to other cases where simple or compound oxides, such as borates, silicates, germanates, sulfates, etc., are introduced.

'Although we definitely prefer not to use alkali metal or other soluble fluorides, it is pose sible to make glasses which resist attack by moisture fairly well from batches containing some fluoride of an alkali metal. It is not necessary to introduce all batch components at one time. In those glasses containing cerium this is in the cerous state, since cerous fluoride is said to be produced from ceric fluoride by heating the latter to 50011130 heat. The glasses "listed are all transparent in that they are clear and transmit light Without objectionable diffusion, even though some wavelengths may be absorbed. The presence of cerium, praseodymium, and neodymium materially reduces the transmission in the invisible portions of the spectrum.

In Table VIII are listed certain optical data of the glasses given in Examples 1, 2, 5, 7, and 8:

TABLE VIII Optical properties 7m 1. 4183 1. 4222 1. 4267 1. 5140 l. 4021 82. 0 81. 0 82. 56. 0 95. 3 0. 00512 0. 00521 0. 00519 0. 00920 0 00422 00359 00365 00363 00651 00296 00281. 00284 00284 00497 00270 00280 00278 00512 00221 1. 00233 00230 l 0. 527 0. 537 0. 536 0. 557 I 0. 524

It is' to be noted that the presence of oxygen ions increases the index of refraction and decreases the Abbe value. In general, the fluorides are compatible with those oxides customarily used in glass batches, and particularly with the oxides of those metals the fluorides of which are herein specified, and the combinations of the two yield useful glasses. These must be distinguished from many hitherto known commercial glasses in the manufacture of which relatively small amounts of fluorides are added but from which the fluorine is largely or completely volatilized during melting at the high temperatures at which such glasses are made. It will be seen that the presence of the fluorides predominantly in glasses containing other known glassiflers with which they are compatible adds to the utility of the glasses of the types made with such other glassiflers.

In the examples given it is to be noted that the fluorides of the flve bivalent elements, magnesium, calcium, strontium, barium, and lead, particularly the first four, are present in varying proportions, totalling between 28 and 45 per cent by weight, and, with lanthanum fluoride, totalling between 35 and 54 per cent. Cerium and thorium fluorides are desirable additions up to per cent. It is to be noted that the given mole percentage of the fluoride of a heavy element such as lead or thorium corresponds to a considerably larger weight per cent when the other elements present are relatively light. The mole and ionic percentages are more useful than weight percentages as definitions of the glass structure. The precise limits of the quantities of the various fluorides that may be usefully employed cannot be stated in general terms. The quantities are dependent largely on such factors as the number, amount, and proportions of ingredients, the thermal history during melting and cooling, the size of the melt and of the mold, and the like.

In the examples given, the ionic percentage of fluorine is between 45 and 65 and that of oxygen between 4 and 20, and the sum of the ionic percentages of fluorine and oxygen is approximately 68 to 7 0, but it may vary between 64 and 72. The highest ionic percentage of oxygen in these glasses is about 20 per cent of the whole or 40 per cent of the fluorine ions in the same batch. It is further to be noted that in the examples the amount of beryllium fluoride lies between 14 and 23 per cent by weight or 32 and 42 mole per cent, and of aluminum fluoride, to per cent by Weight or 13 to 19 mole per cent, and the total of beryllium and aluminum fluorides between and 41 per cent by weight, or 45 and 58 mole per cent. The total of those fluorides of magnesium, calcium, strontium, barium, lead, and lanthanum. that are present is between 35 and 55 per cent of the total by weight, or between and 45 mole per cent; and the total of the compounds containing oxygen is between 8 and 40 per cent by weight and 2 and 25 mole per cent. The ionic percentage of the six metals specifically mentioned totals between 10 and 15; of beryllium, between 9 and 12; of aluminum, between 3 and 6; and of beryllium and aluminum together, between 12 and 18.

Generally speaking, good glasses are not obtained unless at least moderately strong interatomic bonds such as those between beryllium and fluorine form an irregular three-dimensional network. For this the ratios of the number of fluorine atoms to the number of atoms of other elements such as beryllium or aluminum which form strong bonds to fluorine must not be too large. Since a fluoride of a trivalent or tetrayalent element furnishes three or four fluorine atoms for every atom of the trivalent or tetravalent element, large relative proportions in moles of such elements cannot be introduced. On the other hand, even moderate proportions of fluorides of monovalent elements make a glass which is relatively soluble in water and so unstable to attack by atmospheric moisture. We therefore limit the amount of such fluorides to not over 10 per cent by weight or 10 mole per cent, and the ionic per cent of the alkali metal being less than 5. The presence of such fluorides also tends to increase the mobility of the ions in a glass and so facilitates devitrification. For these reasons most of the satisfactory glasses which we have made contain primarily bivalent, trivalent, and tetravalent elements, with the molal proportions of the last two relatively small. Fluorides of the heavy elements are sometimes especially useful components, because they tend to give a glass of high refractive index.

As noted above, the proportions given are by way of example. The structure of a glass is extremely complex, and this is of course increasingly so the greater the number of ingredients, making it practically impossible to obtain equilibrium diagrams showing the same limits of the amounts of fluorides that may be present in the numerous possible combinations. In general, the presence of a considerable number of difierent compounds is preferable to the use of a few, since this reduces the tendency to crystallization or phase separation.

Having thus described our invention, what we claim is:

1. An oxy-fluoride glass consisting of the heat reaction product of a batch in which the following elements are present in the following ionic percentages: fluorine, 48 to 65; oxygen, 4 to 20; the total of fluorine and oxygen being between 64 and 72'; sulphur, l to 3; beryllium, 9 to 12; aluminum, 3 to 6; and the following metals magnesium, 2.76 to 4.40; calcium, 2.66 to 3.81; strontium, 1.11 to 1.60; barium, .89 to 2.50; lead, .92 to 4.03; and lanthanum, .31 to 2.70.

2. Oxy-fluoride glass consisting of metal fluorides and metal oxides and being the heat reaction product of a batch containing in ionic percentages: fluorine, from 45 to 65; oxygen, 4 to 20; fluorine and oxygen together totaling from 64 to 72; beryllium, 9 to 12; aluminum, 3 to 6; magnesium, 2.76 to 4.40; calcium, 2.66 to 3.81; strontium, 1.11 to 1.60; barium, .89 to 2.50; lead, up to 4.03; lanthanum, .31 to 2.70; and phosphorus, up to 6.68 ionic per cent.

3. Oxy-fluoride glass consisting of metal fluorides and metal oxides and being the heat reaction product of a batch containing in ionic percentages: fluorine, from 45 to 65; oxygen, 4 to 20; fluorine and oxygen together totaling from 64 to 72; beryllium, 9 to 12; aluminum, 3 to 6; magnesium, 2.76 to 4.40; calcium, 2.66 to 3.81; strontium, 1.11 to 1.60; barium, .89 to 2.56; lead, up to 4.08; lanthanum, .31 to 2.70; and phosphorus, up to 6.68 ionic per cent; the total of magnesium, calcium, strontium, barium, lead, and lanthanum being from 10 to 15 ionic per cent.

4. Oxy-fluoride glass consisting of metal fluorides and metal oxides and being the heat reaction product of a batch of which by weight fluorides constitute 60 to 92 per cent, and oxides, 8 to 40 per cent; beryllium fluorides, 14 to 23 per cent by Weight; aluminum fluoride, 10 to 20; the total of the said two fluorides being 25 to 41; magnesium fluoride, 5.8 to 10.8; calcium fluoride, 7.0 to 11.7; strontium fluoride, 4.7 to 7.3; barium fluoride, 5.3 to 9.9; lead fluoride, up to 10.5; lanthanum fluoride, 4.5 to 8.2; phosphorus pentoxide, up to 16; and lanthanum oxide, up to 11.6 per cent.

5. Oxy-fluoride glass consisting of metal fluorides and metal oxides and being the heat reaction product of a batch of which by weight fluorides constitute 60 to 92 per cent, and oxides, 8 to 40 per cent; beryllium fluorides, 14 to 23 per cent by weight; aluminum fluoride, 10 to 20; the total of the said two fluorides being 25 to 41; magnesium fluoride, 5.8 to 10.8; calcium fluoride, 7.0 to 11.7; strontium fluoride, 4.7 to 7.3;

barium fluoride, 5.3 to 9.9; lead fluoride, up to 10.5 lanthanum fluoride, 4.5 to 8.2; phosphorus pentoxide, up to 16; and lanthanum oxide, up to 11.6 per cent; the total of the fluorides of magnesium, calcium, strontium, barium, lead, and lanthanum being from 10 to 15 per cent by weight.

6. An oxy-fluoride glass as specified in claim 1 in which the last named six metals total between 10 and 15 ionic per cent of the whole.

KUAN-HAN SUN. MAURICE L. I-IUGGINS.

No references cited. 

1. AN OXY-FLUORIDE GLASS CONSISTING OF THE HEAT REACTION PRODUCT OF A BATCH IN WHICH THE FOLLOWING ELEMENTS ARE PRESENT IN THE FOLLOWING INOIC PERCENTAGES: FLUORINE, 48 TO 65; OXYGEN, 4 TO 20; THE TOTAL OF FLUORINE AND OXYGEN BEING BETWEEN 64 AND 75; SULPHUR, 1 TO 3; BERYLLIUM, 9 TO 12; ALUMINUM. 3 TO 6; AND THE FOLLOWING METALS MAGNESIUM, 2.76 TO 4.40; CALCIUM, 2.66 TO 3.81; STRONTIUM, 1.11 AND 1.60; BARIUM, .89 TO 2.50; LEAD, .92 TO 4.03; AND LANTHANUM, .31 TO 2.70. 